Some Properties of a Hemolysin Produced by Group A β-Hemolytic Streptococci

Abstract

Summary Some properties of a hemolysin produced by group A hemolytic streptococci of the beta type on a meat infusion broth and on an essentially protein free medium are described. A partial purification of the hemolysin has been achieved. The hemolysin is reversibly inactivated by oxidizing agents such as oxygen, hydrogen peroxide, iodine and potassium ferricyanide. Such oxidized hemolysin can be reactivated by a series of thiol compounds, by potassium cyanide and to some extent by leuco methyl viologen, but not by all reducing agents. The hemolysin is also inactivated by cuprous oxide, phenyl mercuric chloride, phenyl mercuric nitrate, alloxan, maleic acid, iodoacetic acid, iodoacetamide and cholesterol. The inactivation caused by each of these, except the last, can be at least in large part reversed by thiol compounds. Many of the results with activating and inactivating reagents suggest that the hemolysin contains and —SH⇄—S—S— oxidation-reduction system and that this system must be in the —SH form in active hemolysin. Some difficulties in accepting this view as the entire explanation are pointed out. The partially purified fractions show all the properties of protein solutions. A typical preparation contained 15.3 per cent nitrogen, 1.9 per cent sulfur and 0.1 per cent phosphorus. Part of the sulfur is present in the form of —SH groups, part as sulfate sulfur and part in undetermined form. The partially purified preparations of hemolysin are neutralized by various antisera, as is the untreated supernatant broth of cultures of hemolytic streptococci. This neutralization is independent of the state of purification or reduction of the hemolysin and is not accompanied by any precipitation, in the available range of concentrations of the reactants. We gratefully acknowledge the supplies of sera received from the Lederle and Squibb Laboratories, the Laboratories of Sharp and Dohme, and the National Drug Company, as well as the strains of bacteria and the streptococcal products received from Dr. David Lackman.